Occurrence of Rotavirus A Genotypes and Other Enteric Pathogens in Diarrheic Suckling Piglets from Spanish Swine Farms

Abstract

Species A rotavirus (RVA) is a major viral pathogen causing diarrhea in suckling piglets. Studies on its genetic heterogeneity have implications for vaccine efficacy in the field. In this study, fecal samples (n = 866) from diarrheic piglets younger than 28 days were analyzed over a two-year period (2018–2019). Samples were submitted from 426 farms located in 36 provinces throughout Spain and were tested using real-time PCR (qPCR) and reverse transcription real-time PCR (RT-qPCR) for five enteric pathogens. The individual prevalence was 89.4%, 64.4%, 44.9%, 33.7% and 4.4% for Clostridiumperfringens, Clostridioides (formerly Clostridium) difficile, species A rotavirus, species C rotavirus and porcine epidemic diarrhea virus, respectively. Most specimens (96.9%) were positive for at least one of the target pathogens, and more than 80% of samples harbored mixed infections. Nucleotide sequencing of 70 specimens positive for RVA revealed the presence of the VP7 genotypes G4, G9, G3, G5, G11 and the VP4 genotypes P7, P23, P6 and P13, with the combinations G4P7 and G9P23 being the most prevalent, and especially in the areas with the highest pig population. The study shows the extensive genetic diversity of RVA strains as well as discrepancies with the genotypes contained in the vaccine available in Spain, and multiple amino acid differences in antigenic epitopes of different G- and P- genotypes with the vaccine strains. Further investigations are needed to determine the efficacy of the vaccine to confer clinical protection against heterologous strains.

Rotavirus A in Domestic Pigs and Wild Boars: High Genetic Diversity and Interspecies Transmission

“…The prevalence in domestic pigs presented in the current study is relatively high (49.9%), similar to previously described studies in Spain [15], Italy [43] and the USA [44]. Most certainly, the predominantly represented young age categories of suckling and weanling pigs, favor the more frequent circulation of RVAs.…”

“…Moreover, the used method of detection has a substantial influence on the final result. Similar to our study, Spanish, Italian and US researchers [15,43,44] used the real-time RT-PCR based method, while in contrast, Taiwanese researchers used the Enzyme Immunoassay as screening and end-point RT-PCR as the confirmatory method [45], which finally resulted in a significantly lower prevalence that is incomparable. Our results indicate that there is no significant difference in the prevalence between the suckling and weanling age categories and between females and males, but the difference in RVA prevalence was significant in diarrheic compared to healthy animals, and in those bred on large holdings compared to the small backyard holdings.…”

“…Apart from reducing RVA build-up through strict hygiene measures, the importance of boosting lactogenic immunity with vaccination remains the most important tool for confronting RVA infection adverse outcomes [2]. Nevertheless, currently, there is no authorized vaccine against porcine RVA in the European Union, yet some pig producers rely on vaccine importation from the USA [15]. In light of the high genetic diversity of porcine RVAs, there are concerns regarding vaccine efficacy on heterologous strains [13,15].…”

“…Nevertheless, currently, there is no authorized vaccine against porcine RVA in the European Union, yet some pig producers rely on vaccine importation from the USA [15]. In light of the high genetic diversity of porcine RVAs, there are concerns regarding vaccine efficacy on heterologous strains [13,15].…”

Development of a triplex quantitative reverse transcription-polymerase chain reaction for the detection of porcine epidemic diarrhea virus, porcine transmissible gastroenteritis virus, and porcine rotavirus A

“…The main pathogens causing diarrhea in piglets are porcine epidemic diarrhea virus (PEDV), porcine transmissible gastroenteritis virus (TGEV) and porcine rotavirus A (PoRVA) (Zhang et al, 2013;Monteagudo et al, 2022). Co-infection by these viruses is common in swine and poses a serious challenge for diarrhea control in swine farms (Zhang et al, 2019;Shi et al, 2021).…”